Reinforced belt having reduced electrical resistivity and method for producing same

ABSTRACT

A link belt for use as a conveyor belt or power transmission belt is provided. The belt is formed of a plurality of links forming a series in successive overlapping relation. The upper surface of each belt link includes an electrically conductive layer. Additionally, the lower surface of each belt link may have an electrically conductive layer. The conductive layer or layers provide an electrical path along the belt to impede the build-up of static electricity as the belt is run during use. 
     A method for producing the conveyor assembly is also provided. A plurality of layers of reinforcing material are arranged in overlapping relation. A binding material such as thermoset urethane is deposited on the reinforcing material to bind the reinforcing materials together, thereby forming a composite material. An electrically conductive layer is deposited on the composite material, forming a conductive layer. The combined conductive layer and composite material are cured so that the conductive layer permanently bonds to the composite material. The combined conductive layer and composite material are then cut into a plurality of belt links, such that the conductive layer of each belt link is generally coextensive with the upper surface of the belt link. The belt links are then assembled to produce a link belt having an electrically conductive path.

FIELD OF THE INVENTION

The present invention relates to interlocking-link conveyor or powertransmission belts and has particular use in applications in which thebelt is used in an environment in which a static charge on the belt isundesirable.

BACKGROUND OF THE INVENTION

Link belts are generally known and used in a variety of applications,such as power transmission belts and conveyor belts. One well known beltis formed of a plurality of layers of reinforced polymer material.Although the belts have been successfully used in a variety ofapplications and environments, the known belts have not been acceptablein environments in which it is critical to prevent static discharge fromthe belt. In the past, several belts have been proposed for preventingthe static build up on belts, however, none of the belts have been ableto provide the performance characteristics needed for power transmissionand/or conveyor applications. Accordingly, there has been a need for ahigh strength link belt that is operable in applications that require abelt that will not build up a significant charge.

SUMMARY OF THE INVENTION

In light of the long-felt need for a useable conveyor or powertransmission belt having a reduced tendency to build-up static, thepresent invention provides a belt having an electrically conductivelayer.

According to one aspect, the present invention provides a link beltformed of a plurality of overlapping interconnected links. Each linkcomprises a connector for connecting the link with an adjacent link.Each link is formed of a matrix material, a reinforcement layer and aconductive layer. The reinforcement layer is embedded within the matrixmaterial and has a higher modulus of elasticity than the matrixmaterial. The conductive layer is formed at an outer layer of the matrixmaterial and has a resistivity that is substantially less than theresistivity of the matrix material. Additionally, the conductive layermay be formed of a sheet of metal fibers.

According to another aspect, the present invention provides a link beltformed of a plurality of links. Each link has an upper conductive layer,a lower conductive layer and a matrix material between the conductivelayers. A reinforcement layer is embedded in the matrix material toprovide tensile strength for the links. When the links are connected,contact points between the conductive layers of adjacent links providean electrically conductive path along the length of the belt to impedethe build-up of static charge on the belt.

According to another aspect, the present invention provides a method forproducing a link belt having a reduced tendency to a build-up staticcharge. The method includes the steps of providing a binding materialand reinforcing the binding material with a reinforcement layer. A sheetof conductive material is applied to the top layer of the bindingmaterial before the binding material is cured. The binding material,reinforcement layer and conductive layers are then cured together tocreate belt material, which is cut into a plurality of belt links. Thelinks are connected to form a series of successive overlapping links bymechanically interlocking and overlapping successive links in such amanner that a plurality of electrically conductive points from a linkare in electrically conductive relationship with an adjacent link.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary and the following detailed description of thepreferred embodiments of the present invention will be best understoodwhen read in conjunction with the appended drawings, in which:

FIG. 1 is a side view of an link belt assembly having reduced electricalresistivity shown engaged by a driving mechanism for the assembly.

FIG. 2 is a top view of an individual link of the belt shown in FIG. 1prior to assembly.

FIG. 3 is a side view of the individual belt link shown in FIG. 2.

FIG. 4 is a fragmentary side view partially in section, of the beltshown in FIG. 1.

FIG. 5 is a plan view of the belt shown in FIG. 4.

FIG. 6 is a fragmentary side view partially in section, of an alternatebelt.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings in general and FIG. 1 specifically, a belthaving an electrically conductive path 40 is designated generally 10.The belt 10 is shown entrained about two pulleys 5. The electricallyconductive path 40 impedes the build-up of a static charge on the belt.Although the belt is illustrated as a conveyor belt, the belt 10 couldbe a transmission belt for transmitting power from a drive element to adriven element, such as transmitting power from a drive pulley to adriven pulley. In a preferred embodiment, the belt 10 is a link beltformed of a plurality of links each having a surface that forms theelectrically conductive path 40.

Referring now to FIGS. 4 and 5, the belt 10 preferably comprises aseries of interlocking belt links 20. One of the individual links 20that comprise belt 10 is illustrated in FIGS. 2 and 3. Each belt link 20has a body portion 22 and a fastener 30 connected to the body portion.In the present instance, the thickness of the belt link 20 between thetop surface and the bottom surface is substantially uniform throughoutthe entire link.

An electrically conductive layer is permanently bonded to one of theouter surfaces of each belt link. The conductive layer may be either thetop layer of the belt link or the bottom layer. In the present instance,each link includes both a top conductive layer 35 and a bottomconductive layer 36. Additionally, in the present instance, theconductive layers are coextensive with the top/bottom surfaces of thebelt link 20. When the belt links 20 are assembled to form a belt 10,the conductive layers 35,36 on adjacent links contact one another toform electrically conductive paths, as discussed further below.

The body portion 22 of the belt link 20 is generally rectangular, havingtwo edges 25 extending longitudinally between a leading end 23 and atrailing end 24, both of which extend transversely between the twoedges. Adjacent leading end 23 a leading aperture 29 extends through thethickness of body portion 22. Longitudinally spaced from the leadingaperture 29, adjacent the trailing end 24, a trailing aperture 28extends through the thickness of body portion 22.

The leading end 23 corresponds to the direction in which the assembly 10travels as shown by the arrow in FIG. 4. However, the direction in whichthe assembly 10 travels can be reversed so that the leading end 23 doesnot lead the trailing end 24 with respect to the actual travel of theassembly.

The fastener 30 integrally connects the body portion 22, and comprises afastening tab 32 and a constricted neck 33. The neck extendslongitudinally, with one end connected to the fastening tab 32, and theother end connected to the trailing end 24 of body 22. The length of theneck 33 between the trailing end 24 and the fastening tab 32 issufficiently long to allow the fastening tab 32 to extend through theapertures in two belt links 20 as will be further discussed below.

The fastening tab 32 is generally trapezoidal shaped, having twoparallel ends that are transverse the neck 33. The fastening tab 32 issubstantially wider than the neck 33, being widest at the point where itintersects the neck, and tapering as it extends away from the neck.

The belt links 20 are connected by passing the link fasteners throughthe apertures in adjacent belt links. To ensure that the belt links canproperly connect, the apertures are configured and dimensioned withreference to the fastening tab and the neck.

In the present instance, the apertures through body 22 are non-circular.Both apertures 28 and 29 are longitudinally elongated so that theirlength is greater than their width. To ensure that fastening tab 32 canpass through the apertures, the length of the apertures is greater thanthe greatest width of the fastening tab 32.

The width of apertures 28 and 29 is not constant. Instead, the apertureswiden as they extend toward leading end 23. To provide proper connectionbetween the belt links 20, the apertures are narrower than the fasteningtab width so that the fastening tab 32 cannot pass back through theapertures once the belt links are connected. However, the apertures arewider than the neck 33 to allow the neck to extend through the apertureswhile the belt links are connected, as will be discussed below.

The belt links 20 are made of a material of sufficient tensile strengthto convey the weight of the workpiece or transmit the necessary power,if used in a power transmission application. In the preferredembodiment, the belt links 20 are made of a thermoset urethane that isreinforced with a polyester fabric.

Because the belt links have sufficient tensile strength to convey theweight of the workpiece, the material used to make the conductive layer35 can be chosen according to characteristics such as resistivity andflexibility, without significant regard to its tensile strength. Avariety of conductive elements can be used to form the conductive layer,such as metal, carbon, carbon fiber or highly conductive polymers. Inthe present instance, the conductive layer is a layer of conductivematerial, such as a metal material, and as shown in FIGS. 2 and 5, theconductive layers is a mesh, such as a mesh of metallic fibers. Morespecifically, in the present instance, the conductive layer is a layerof fabric that is coated with metal.

As stated above, the electrically conductive layer may be along the topor bottom surfaces of the links, and in the present instance are at thetop and bottom surfaces. It should however be understand that theconductive layer being at the top or bottom surface does not mean thatconductive material is necessarily an exposed surface at the top orbottom surface of the link. During the manufacturing process, somematerial may coat the conductive material. For instance, a thin layer ofbinder material may coat the conductive material. This is particularlytrue for materials such as a mesh or a fabric in which the binder islikely to squeeze through the mesh. However, in the present instance,the conductive materials are substantially close to the outer surface ofthe top and bottom surfaces so that the layer of material coating theconductive material is less than the thickness of the conductivematerial.

It should be noted that the thickness of each conductive layer isexaggerated in the Figures for illustrative purposes. In actuality, thethickness of each conductive layer is minimal compared to the overallthickness of the belt links. For instance, the thickness of each link isapproximately 0.200 and each conductive layer is less than 0.050″.Specifically, the conductive material is between 0.005″ and 0.025″thick, and in the present instance, the conductive material is 0.015″thick.

As previously stated, the interlocking-link belt 10 has a conductivelayer 40, and is comprised of a plurality of belt links 20 that havebeen described above. The following discussion describes theinterconnections between the belt links 20 that form the belt 10.

As shown in FIGS. 4 and 5, a series of belt links 20 are arranged in asuperimposed successive overlapping relation to form the belt 10 with aconductive layer 40. The bottom of each belt link overlaps the top of anadjoining belt link, so that the thickness of the belt 10 is at leasttwice the thickness of an individual belt link 20.

FIG. 4 illustrates a portion of the assembly 10, showing how theconductive layers interact to form a conductive path when the belt linksare interconnected. Included in these views is the connection between abelt link 20A, and the two succeeding belt links, 20B, and 20C. In thisconnection, the fastening tab 32A of belt link 20A passes sidewaysthrough apertures in the two succeeding belt links. It first passesthrough the trailing aperture 28B of the adjacent succeeding belt link20B and then passes through the leading aperture 29C of the nextsucceeding belt link 20C.

The term trailing is used with respect to the direction the assemblytravels, as shown in by the arrow in FIG. 4. Because the direction oftravel can be reversed, the preceding belt links can be succeeding withrespect to the actual travel of the assembly 10.

After passing through the aperture in belt link 20C, the belt linkfastening tab 32A is twisted to bear against the bottom surface 36C ofbelt link 20C. When connected in this way, the top surface 35A of beltlink 20A is the top side 11 of belt 10, and the bottom surface 36C ofbelt link 20C is the bottom side 12 of belt 10.

The configuration of the links and how they are connected provides aplurality of electrically conductive paths between the belt links. Forinstance, From FIGS. 2 and 3 it can be seen that the electricallyconductive layers extend to the edges of the belt link 20. Additionally,the electrically conductive layers extend to the edges of the fastener30 including the locking tab 32. As shown in FIG. 4, the fastener 30bears against the bottom surface of one of the preceding links, and thebottom surface of a link contacts the upper conductive layer of thepreceding link. Additionally, the neck 33 may contact one of theconductive layers 35, 36 of either of the links that the neck passesthrough. These numerous points of contact provide numerous potentialelectrically conductive paths.

One of the electrical pathways is the electrical path between the belt10 and the pulleys 5. Specifically, the exposed conductive edges of thebody 22 of each link 20 form electrical pathways between the links andthe pulleys 5. The pulleys are formed of conductive material, such asmetal, and are grounded, such as by being connected to the frame of themachine or otherwise. Therefore, the connection between the belt 10 andthe pulleys provides an conductive pathway between the belt and thepulleys 5. In this way, any static that would otherwise tend to build upon the belt, will tend to conduct through the conductive layer and thento the pulleys to dissipate the static electricity.

Although the link belt can be formed so that each link only overlaps asingle preceding belt, as discussed above, in the present embodimenteach link overlaps two adjacent links, as shown in FIG. 4. Therefore,each link is potentially in electrically conductive contact with twoadjacent links, thereby providing parallel electrical paths betweenadjacent links.

For instance, referring to FIGS. 4 & 5, link 20 a overlaps links 20 band 20 c. Therefore, the neck 33 of link 20 a passes through thetrailing aperture 28 b of link 20 b and the leading aperture 29 c oflink 20 c. As discussed previously, the conductive layers 35, 36 extendto the edge of the links. Therefore, the edges of the apertures 28, 29have electrically conductive points that can contact electricallyconductive points along the edge of the neck 33 c. In this way, theconductive layers 35 a, 36 a of link 20 a are connected with theconductive layers 35 b, 35 c and 36 b, 36 c of links 20 b and 20 c viathe neck 33 a of link 20 a. Similarly, link 20 b is connected with link20 c and the next trailing link via the exposed edges of the connector30 and the neck 33. In this way, the overlapping links also provide aplurality of overlapping parallel pathways between the conductive layersof adjacent links. Therefore, if one or more of the conductive paths isinterrupted between two links at one point, one of the alternateparallel connections may provide the electrical pathway between theadjacent links to maintain a conductive path along the length of thebelt.

Additionally, the belt may include more than two overlapping links,which would provide even more parallel paths to maintain the conductivepath. Specifically, as described above, each link overlaps two adjacentlinks. However, in certain applications it is desirable to configure thebelt so that each belt link overlaps three or more adjacent links. Insuch an embodiment, the links includes further apertures and theconnector for each link goes through three or more adjacent links. Inthis way, each connector provides a parallel path electricallyconnecting a link with three adjacent links.

In the foregoing description, the embodiment of the belt 10 is describedas being formed of links 20, each of which has a connector 30 that isintegrally formed with the body of the link. However, the link belt 10may be formed of links that utilize a separate connector. For instance,the connector may be a rivet 230 that connects the adjacent links, suchas shown in the belt 210 in FIG. 6. Alternatively, the connector may bea fastening stud having an elongated head that passes through aperturesin each belt link. Such fastening studs have enlarged heads that bearagainst the lower surface of the links similar to the manner in whichthe connecting tabs 32 bear against the bottom surface of the links asdescribed above.

It should also be understood that the configuration of the apertures mayvary when using an alternative connector. For instance, when usingrivets it is desirable to use a more rounded hole, rather than theelongated apertures 28, 29 described above. On the other hand, whenusing studs, the aperture may be more elongated or slot-like.

One of the advantages of using a separate connector is that suchconnectors are frequently formed of a conductive material such as steel.Therefore, the separate connectors may provide an improved electricalconnection between the conductive layers on adjacent layers.Additionally, the connectors may be formed of a material that resistssparking, such as brass or aluminum.

The belt 10 is produced as follows. The belt links 20 that make up thebelt 10 include at least one layer of reinforcing material, such aswoven polyester sheet. The reinforcing material is impregnated with abinding material to form a composite material. The binding material isliquified and deposited onto the reinforcing material while liquid.Preferably, the composite material includes a plurality of layers ofreinforcing material and the binding material is a thermoset urethane.

The conductive layers 35, 36 are laid on the composite material,preferably while the binding material is wet. In other words, preferablythe conductive layers are laid onto the composite material before thecomposite material is cured or dried. The conductive material may besprayed on or poured on, or the composite material may be partiallysubmerged in a bath of conductive material. However, preferably theconductive layers are sheets of electrically conductive material thatare laid onto the binder and reinforcement layers. For instance, in thepresent instance, the electrically conductive materials are metallizedfabric materials that are approximately coextensive with the upper/lowersurface of the reinforcement material. One material that provides adesirable resistivity is a non-woven point bonded polymer fabric that iscoated with a metallic material, such as a nickel silver alloy. Sincethe binding material of the composite material is wet when theconductive sheets are placed onto the composite material, the conductivesheets adhere to the binder with the reinforcement layers.

After the conductive sheets are laid together with the binder andreinforcement material, the combination is the pressed together underhigh pressure. After the layers are pressed together, the combination iscured. During the curing process the conductive layers 35, 36permanently bond to the composite material.

Ordinarily the cured material is at least several times wider that thewidth of the belt links 20. The cured material is therefore cut into aplurality of elongated strips approximately as wide as the width of abelt link 20. The belt links are then cut-out from the strips of curedmaterial. In the present instance, the belt links are formed bypunching, which also simultaneously punches the rearward and forwardapertures in the belt links.

Formed in this way, the belt links 20 have two integral conductivelayers forming the top and bottom surfaces 35, 36 of the belt link. Theconductive layers are coextensive with the substrate material formingthe belt link 20 which in the present instance is polyester reinforcedthermoset urethane.

The belt links 20 are assembled to form a continuous interlocking linkbelt 10. The belt links 20 are connected to one another as detailedabove and shown in FIGS. 4 and 5.

In the foregoing example, the belt links have been formed with theconductive layers positioned at the top or bottom surface of the beltlinks. In an alternative embodiment, the conductive layer or layers maybe positioned within the matrix. For example, in an alternativeembodiment, a layer of conductive material may be embedded within themiddle of the belt links. In such an embodiment, the matrix materialwill insulate the conductive layer from providing an electricallyconductive path with the at the upper or lower surfaces of the beltlinks. However, as discussed previously, the conductive layer extends tothe edges of the links. Accordingly, the conductive layer forms a seriesof exposed electrically conductive points at the edges of the links.When the links are interconnected, the exposed electrically conductivepoints of adjacent links provide paths between the links.

For instance, when the conductive layer is disposed within the center ofthe matrix, the conductive layer is exposed at the edges of theconnector 30. Therefore, the conductive layer is exposed to the surfacealong the edges of the connector neck 33. Similarly, conductive layersis also exposed at the interior edges of the apertures 28, 29. When thelinks are combined to form a belt, the neck 33 of the connector 30passes through the apertures 28, 29 of two links, as shown in FIGS. 4-5for the embodiment discussed above. Accordingly, the edges of the neck33 contact the interior edges of the apertures 28, 29. In this way, theexposed edge of the conductive layer along the neck provides one or morepoints for providing an electrically conductive path with the conductivelayer of two adjacent links.

Although the electrical pathway between the links may have a higherresistance when the conductive layer is embedded within the links, theelectrical pathway may still be sufficiently low to impede theaccumulation of a static charge on the belt during operation.Additionally, since each link is connected with two adjacent links, theconductive layers are connected to one another in parallel connections.Therefore, if the connection between the neck of one link and theaperture of an adjacent link to not make sufficient contact to providean electrically conductive pathway, one of the parallel connections mayprovide the electrically conductive pathway between the links.

In yet another embodiment, the reinforcement layer may be integratedinto the conductive layer. For instance, as described above, theconductive layer may be a layer of fabric, such as a non-woven fabric.The fabric is then coated with an electrically conductive material, suchas metal. Therefore, the fabric may selected so that it has a sufficienttensile strength to withstand the load requirement of the belt. Thereinforcing fabric can then be coated with an electrically conductivematerial, such as metal. The reinforcing fabric and layer of metal arethen embedded within the matrix material to reinforce the link. Theelectrically conductive path between adjacent links would be similar tothe embodiment described above in which the conductive layer is embeddedwithin the link. Depending on the tensile strength requirement of thebelt, additional reinforcement layers may also be embedded within thebelt. The additional reinforcement layers may or may not include aconductive layer, depending on the operational requirements and costconstraints.

Although in the preferred embodiment, the belt is a link belt, thepresent invention is broad enough to include other types of belts, suchas endless belts (i.e. belts made of a single length of material withthe ends spliced together to form the belt). In the situation of anendless belt, the belt material can be formed as described above andthen cut into lengths of belt of the appropriate length and width. Theends are then joined using any of a variety of known joints for splicingtogether a belt, such as a splice joint that is mechanically fastened orbonded with an adhesive. The edges of the assembled belt are thentrimmed.

It will be recognized by those skilled in the art that changes ormodifications may be made to the above-described embodiments withoutdeparting from the broad inventive concepts of the invention. It shouldtherefore be understood that this invention is not limited to theparticular embodiments described herein, but is intended to include allchanges and modifications that are within the scope and spirit of theinvention as set forth in the claims.

1. A link belt entrained about a conductive pulley, comprising: aplurality of overlapping interconnected links, wherein each linkcomprises: a connector for connecting the link with an adjacent link; amatrix material having a modulus of elasticity and a conductivity; areinforcement layer embedded within the matrix material having highermodulus of elasticity than the matrix material; and a conductive layerformed at an outer layer of the matrix material, wherein the conductivelayer has a resistivity that is substantially less than the resistivityof the matrix material, and wherein the conductive layer is formed sothat the conductive layer extends to the edges of the links to form aconductive connection with the conductive pulley.
 2. The link belt ofclaim 1 wherein the conductive layer comprises metal fibers comprise anon-metallic substrate with a metallic outer layer.
 3. The link belt ofclaim 1 wherein the conductive layer comprises a sheet of electricallyconductive metallic textile.
 4. The link belt of claim 1 wherein theconductive layer is less than approximately 0.050″ thick.
 5. The linkbelt of claim 1 wherein the conductive layer is between approximately0.005″ and 0.025″ thick.
 6. The link belt of claim 1 wherein theconductive layer comprises a plurality of conductive contacts points toprovide an electrically conductive path along a plurality of pointsbetween adjacent links.
 7. The link belt of claim 6 wherein theplurality of points create an electrically conductive path along thelength of the belt.
 8. The link belt of claim 6 wherein the surfaceresistivity between an outer surface of adjacent belt links is less thanapproximately 10,000 ohms per square.
 9. The link belt of claim 8wherein the surface resistivity between an outer surface of adjacentbelt links is less than approximately 1,000 ohms per square.
 10. Thelink belt of claim 8 the surface resistivity of the upper and lowersurfaces of the belts links is less than approximately 10,000 ohms persquare.
 11. The link belt of claim 8 wherein the connector for a linkprovides an electrically conductive path between the link and a link towhich the connector is connected.
 12. A method for producing a linkbelt, comprising the steps of: providing binding material; reinforcingthe binding material with a layer of reinforcing material to create alayered material; applying a sheet of conductive material to the top ofthe layered material before the binding material is cured; curing theconductive sheet together with the layered material to create beltmaterial; cutting a plurality of links from the belt material, whereinthe links are cut so that conductive material is sufficiently exposed toprovide electrically conductive points along an outer edge of the links;connecting the plurality of links to form a series of successiveoverlapping links to form a length of belt, wherein the step ofconnecting the plurality of links comprises the step of mechanicallyinterlocking and overlapping successive links in such a manner that aplurality of electrically conductive points from a link are inelectrically conductive relationship with an adjacent link; andentraining the length of belt around an electrically conductive pulleyso that the electrically conductive points along the outer edge of thelinks in in electrically conductive relationship with the conductivepulley.
 13. The method of claim 12 comprising the step of applying asecond sheet of conductive material to the bottom of the layeredmaterial before the binding material is cured.
 14. The method of claim13 wherein the step of connecting the plurality of links comprisesconnecting the links so that the top layer of conductive material from afirst link is in electrically conductive relationship with the bottomlayer of conductive material of an adjacent link.
 15. The method ofclaim 13 wherein the step of connecting the plurality of links comprisesconnecting the links so an electrical path is created between the topconductive layer of a link and the bottom conductive layer of adifferent link.
 16. The method of claim 13 wherein the step of applyinga sheet of conductive material comprises applying a non-woven fabriccoated with metallic material.
 17. A link belt, comprising: a pluralityof overlapping interconnected links, wherein each link comprises: amatrix material that is a generally insulative material; a reinforcementlayer embedded within the material having greater modulus of elasticitythan the matrix material; an upper conductive layer disposed at the topsurface of the matrix material; and a lower conductive layer disposed atthe bottom surface of the matrix material. wherein the upper and lowerconductive layers have a resistivity that is substantially less than theresistivity of the matrix material.
 18. A link belt, comprising: aplurality of overlapping interconnected links, wherein each linkcomprises: a conductive layer; a matrix material having a resistivitythat is substantially greater than the resistivity of the conductivelayer; a reinforcement layer embedded within the matrix material havinggreater modulus of elasticity than the matrix material; an aperturethrough the thickness of the link, wherein the aperture has an internaledge and the conductive layer forms one or more exposed electricallyconductive points at the internal edge of the aperture; and a pluralityof connectors for connecting the links together, wherein the connectorscomprise an exposed electrically connective point along an outersurface, wherein each connector provides an electrically conductive pathbetween a link and one or more of the exposed electrically conductivepoints at the internal edge of the aperture of an adjacent link.
 19. Thelink belt of claim 18 wherein the exposed electrically connective pointis in electrically conductive communication with one or more of theexposed electrically conductive points of the aperture of the adjacentlink.
 20. The link belt of claim 18 wherein the conductive layer is atan outer surface of the belt link.
 21. The link belt of claim 18 whereinthe connectors are integrally formed with the links so that each linkcomprises an integrally formed connector.